This invention comprises an ultrasonic guide wire for insertion into arteries to disintegrate clots (thrombi) which accumulate on disrupted cholesterol plaques. The device proposed introduces a new form of treatment for arterial occlusions and obstructions. This new therapy may be called dispersion or disintegration thrombectomy.
Over time, cholesterol plaque builds up in coronary arteries. Later in life, these build-ups are attacked by the body's own immune system. These build-ups also become susceptible to ulceration and disruption. The tissue layer, or endothelial cap, that covers the plaque is attacked by white cell enzymes. The consequent thinning of the cap makes it susceptible to tearing by shear forces, exposing oxidized cholesterol contained within the plaque to the bloodstream. The body's clotting mechanism interprets this exposure as a perforation of the artery and activates to seal “the hole”. Clot builds up on the obstructed plaque. The clot may obstruct the vessel and produce a syndrome called unstable angina. The volume of clot may be so large that it occludes the vessel and produces acute myocardial infarction (heart attack). Collectively, these events are called the acute coronary syndromes.
Increasingly, acute coronary syndromes are treated with percutaneous intervention. Current methods comprise threading a guide wire through the arterial obstruction or occlusion, and then sliding a balloon angioplasty catheter to the site of plaque disruption and clot formation. The balloon is inflated, fragmenting and dispelling the clot. Alternatively, a coronary stent may be deployed to reopen the artery, and trap the clot in its mesh structure. Unfortunately, with both of these methods, clot fragments are carried downstream and lodge in the capillaries of the heart muscle. This produces necrosis (patches of dead heart muscle) and reduces the function of the main pumping chamber called the left ventricle. The scarring, which results, may become the source of fatal heart rhythms. Worse yet, sludging of the fragments in the capillary bed may reduce blood flow, and result in a dangerous fall in blood pressure, or even patient death. None of the devices and methods proposed or developed to address these problems has been universally successful.
Some existing devices endeavor to capture clots downstream. These devices typically contain a deployable basket on a guide wire, but the baskets do not always expand completely within the downstream vessel. As a result, some clot slips around the edges of the basket.
Catheters designed to aspirate the thrombus do reduce the volume of a clot, but the impact is limited as demonstrated in recent scientific studies. Some clot remains attached to the plaque.
Consequently, there is a need for a device or apparatus which can remove up to 100% of the clot and mitigate fragment embolization downstream into the capillary bed of the heart muscle.